硫化氢在肾脏纤维化中的作用及其机制研究

Renal fibrosis is the common pathway to end stage renal disease(ESRD) and also the leading pathological characteristic of chronic kidney disease(CKD). Renal fibrosis provides an promising therapeutic target, since a large variety of pathophysiologically distinct renal diseases finally converge into this single process.The mechanisms associated with renal fibrosis have not been fully elucidated and effective therapies are still scare. RAS inhibitors are indisputably the first line drugs in combating renal fibrosis. However, these drugs increase the risk of renal function deterioration and hyperpotassaemia when serum creatinine rises above 265ummol/L.It has been recently found that the plasma level of hydrogen sulfide(H2S) was decreased in patients with CKD and uremia, indicating that CKD is a disease with H2S deficiency, but the physiological function of H2S in CKD is still unknown. Evidences from other organs have shed light on the anti-fibrotic effect of H2S on heart, lung and liver.Therefore, we tested whether this anti-fibrotic effect is also applicable in kidney disease. Our preliminary data demonstrated that H2S inhibited the differentiation of renal fibroblast into myofibroblast. We therefore postulated that H2S was able to attenuate renal fibrosis. This project is designed to explore the roles of H2S in the proliferation and differentiation of renal interstitial fibroblasts, to assess whether fibrotic features in the unilateral ureter obstruction animal model can be inhibited by H2S, and finally to determine whether the anti-fibrotic effect of H2S is mediated by the closure of the Kca3.1 channel in renal fibroblasts，as well as via the inhibition of the TGFβ1-smad-MAPK signal pathway.Several techniques, such as RT-PCR, Western Blot, whole cell patch clamp, immunohistochemisty and various research methods including pharmacological targeting (H2S donor,agonist and antagonist of CSE,etc), overexpression and knock down of CSE gene will be applied. The present study will contribute to clarify the the physiological function of H2S in CKD and the mechanisms of its anti-fibrotic effect. Moreover, we bring up with a new therapeutic strategy in renal fibrosis which can bypass the serious adverse effects of RAS inhibitors.The progression of CKD will hopefully be slowed or halted by this therapy and the incidence of uremia is therefore possibly reduced.

肾脏纤维化是慢性肾脏病（CKD）的重要病理特征，其发病机制尚未完全阐明，也缺乏有效的治疗药物。近年发现CKD患者血浆硫化氢（H2S）含量下降，提示CKD是一种伴有H2S缺乏的疾病，但CKD中H2S的生理作用不明。我们的预实验结果证实H2S抑制了肾间质成纤维细胞分化为肌纤维母细胞，提示 H2S有抗肾脏纤维化作用，但其机制还不明确。在此工作基础上本研究运用RT-PCR、Western Blot、膜片钳、细胞免疫荧光、过表达和沉默CSE基因等技术，结合药理学方法探讨H2S对肾间质成纤维细胞增殖和分化的影响；研究H2S对单侧输尿管梗阻动物模型肾间质纤维化的作用；并从TGF-β-smad 、MAPK信号途径以及Kca3.1离子通道角度探讨H2S抗纤维化的分子机制。本研究有望阐明H2S在CKD中的生理作用及其抗纤维化机制，为临床治疗肾脏纤维化提供新的思路，从而延缓CKD进展，降低尿毒症发病率。

肾脏纤维化是慢性肾脏病（CKD）的重要病理特征，其发病机制尚未完全阐明，也缺乏有效的治疗药物。近年发现CKD患者血浆硫化氢（H2S）含量下降，提示CKD是一种伴有H2S缺乏的疾病，但CKD中H2S的生理作用不明。本研究在两种CKD模型（单侧肾梗阻模型和腹膜透析腹膜炎模型）中发现腹腔注射小剂量NaHS（5.6-56ug/kg/d）能够改善CKD动物模型中纤维化，改善腹膜功能和肾功能，模型中的炎症因子（IL-6、MCP-1等）和新生血管（CD33）表达均明显减少，而大剂量NaHS（560ug/kg/d）具有毒性作用。细胞学实验还证实NaHS能够抑制TGF-β-smad 和MAPK信号途径所致的肾脏成纤维细胞分化，以及FBS所致的成纤维细胞的增殖。本研究提示H2S在CKD中的生理作用之一是具有抗肾脏纤维化作用，其机制是通过抑制炎症反应、抗成纤维细胞和新生血管增殖而介导的。本研究还明确了H2S治疗CKD的有效剂量范围，为临床使用H2S治疗肾脏纤维化提供了理论依据，从而延缓CKD进展，降低尿毒症发病率。